In many instances, users carrying electronic mobile devices may enter a building structure that blocks reception of GNSS signals. GNSS, in general, includes global positioning systems (GPS), Galileo, Global Navigation Satellite System (GLONASS (Russia)) and Compass, as well as other systems. Traditionally, geographical positions such as altitude, longitude and latitude can be calculated with GNSS signals of four or more satellites. The geographical information may enhance social interaction. Using GNSS signals for identifying geographical positions can sometimes be limiting or impossible if the environment denies reception of the GNSS signal, such as in a building, a basement, underwater, etc.
Like reference symbols in the various drawings indicate like elements.